Recent research has revealed that periodontal disease (gum disease) may be a far more serious threat to overall systemic health than previously realized. Periodontitis, a form of periodontal disease, is a tissue destructive process resulting from the accumulation of pathogenic bacteria along the gingival margin and the consequent tissue destructive host response to these pathogens. The presence of periodontitis can also result in the release of bacteria and/or bacterial toxins into the bloodstream. The host responses to the presence of these bacterial pathogens and/or toxins in the bloodstream may contribute to the development of atherosclerosis (heart disease), increase the risk of premature, underweight babies; and pose a serious threat to people whose health is compromised by diabetes, severe respiratory diseases, stroke and bacteremia (bacteria in the blood).
For a long time, it has been known that bacteria may affect the heart. Now evidence is mounting that suggests people with periodontitis, a bacteria-mediated disease, may be more at risk for heart disease, and have a significantly higher risk of having a fatal heart attack, than patients without periodontitis. Heart disease is the leading cause of death in most developed countries, and periodontitis is one of the most common bacterial-mediated diseases in humans, affecting as many as one third of those over 50. Thus even if periodontitis has only a modest effect on increasing the risk of heart attack, its prevalence may make it a significant contributor to the risk for heart disease in the population as a whole.
Several theories exist to explain the link between periodontal disease and heart disease. One theory is that oral bacterial pathogens enter the blood through inflamed gums, attach to fatty plaques in the coronary arteries (heart blood vessels) and cause small blood clots that contribute to clogged arteries. Researchers have found that 70% of the fatty plaque that blocks carotid arteries and causes stroke contains bacteria. Forty percent of those bacteria have been traced to the mouth. Coronary artery disease is characterized by a thickening of the walls of the coronary arteries due to the buildup of fatty proteins. Blood clots can obstruct normal blood flow, restricting the amount of nutrients and oxygen required for the heart to function properly. This may lead to heart attacks. Another possibility is that changes in systemic inflammatory mediators caused by periodontitis increase development of atherosclerotic plaque, which then contributes to thickening of the arterial walls.
Research also suggests that people with diabetes are more likely to have periodontitis than people without diabetes, and the presence of periodontitis may make it more difficult for diabetics to control their blood sugar. It is known that the presence of periodontitis can increase blood sugar, contributing to increased periods of time when the body functions with a high blood sugar level, which puts a diabetic person at increased risk for diabetic complications. Thus, controlling periodontitis may help control diabetes. A recent study (“Heightened Gingival Inflammation and Attachment Loss in Type 2 Diabetics with Hyperlipidemia,” in Journal of Periodontology, November, 1999) found that poorly controlled type 2 diabetic patients are more likely to develop periodontal disease than well-controlled diabetics. The study further explains why diabetics are more susceptible to severe periodontal disease. The study concluded that poorly controlled diabetics respond differently to bacterial plaque at the gum line than well-controlled diabetics and non-diabetics, possibly due to elevated serum triglycerides. Poorly controlled diabetics have more harmful proteins (cytokines) in their gingival tissue, causing destructive inflammation of the gums. In turn beneficial proteins (growth factors) are reduced, interfering with the healing response to infection. “Increased serum triglyceride levels in uncontrolled diabetics seem to be related to greater attachment loss and probing depths, which are measures of periodontal disease,” said Christopher Cutler, D.D.S., Ph.D., the study's lead researcher.
Evidence is also mounting that suggests pregnant women who have periodontitis may be significantly more likely to have a premature, low-birthweight baby. The inflammatory response prompted by periodontitis and/or the associated presence of bacterial pathogens/toxins in the bloodstream are cause for concern among pregnant women because they pose a risk to the health of the fetus. The presence of periodontitis appears to retard fetal growth by releasing into the woman's bloodstream bacterial toxins that reach the placenta and interfere with fetal development by increasing systemic levels of inflammatory mediators that could prompt pre-term birth. Scientists have also proposed that the presence of a low-grade infection may influence harmed cells to discharge inflammatory chemicals, similar to those used to induce abortion. This can cause the cervix to dilate and set off uterine contractions. The risk of having a premature baby of low birth weight was estimated to be at least 7.5 times as high for women with severe periodontal disease, and to occur in 5 percent of pregnancies, costing the U.S. $5.7 billion a year. [S. Offenbacher, J. Periodontol. 1996 October; 67(10 Suppl): 1103-13].
Research further suggests that periodontal disease may pose an increased risk for severe respiratory diseases like pneumonia, bronchitis, emphysema and chronic obstructive pulmonary disease.
The VA Dental Longitudinal Study (DLS) and Normative Aging Study (NAS) examined the relationship of periodontal disease to mortality from all outcomes and concluded that periodontal status at baseline was a significant and independent predictor of mortality. [Annals of Periodontology, 3(1), 339-49, July 1998] The study was conducted starting in the mid-1960s among men on good medical health and followed over more than a 25-year period. It was found that for each 20% increment in mean whole-mouth ABL (alveolar bone loss, measured with a Schei ruler using full-mouth series of periapical films), the subject's risk of death increased by 51%. The risk of death was also found to be associated with periodontal status as measured clinically by periodontal probing depth. Subjects in the population group with the deepest average probing depths were found to be at 74% higher risk.
According to Dr. Michael Roizen, University of Chicago internist and anesthesiologist, keeping teeth and gums healthy adds 6.4 years to a person's life. Indeed, the American Academy of Periodontology (AAP) concurs that keeping teeth and gums healthy is as significant as taking vitamins, quitting smoking and reducing stress as among the top things that a person can do to add years to life.
Periodontal disease (“gum disease”) is a broad term used to describe those diseases which attack the gingiva and the underlying alveolar bone supporting the teeth. The disease exists in a number of species of warm blooded animals such as humans and canines, and includes a series of diseases exhibiting various syndromes which vary from each other according to the stage or situation of the disease or the age of the patient. The term is used for any inflammatory disease which initially occurs at a marginal gingiva area and may affect the alveolar bone. Periodontal disease affects the periodontium, which is the investing and supporting tissue surrounding a tooth (i.e., the periodontal ligament, the gingiva, and the alveolar bone). Two common stages of periodontal disease are gingivitis (inflammation of the gingiva) and periodontitis (inflammation of the periodontal ligament manifested by progressive resorption of alveolar bone, increasing mobility of the teeth, and loss of the teeth at advanced stage). Combinations of inflammatory and degenerative conditions are termed periodontitis complex. Other terms used for various aspects of periodontal disease are “juvenile periodontitis”, “acute necrotizing ulcerative gingivitis”, and “alveolar pyorrhea”.
Periodontal disease may involve one or more of the following conditions: inflammation of the gingiva, formation of periodontal pockets, bleeding and/or pus discharge from the periodontal pockets, resorption of alveolar bone, loose teeth and loss of teeth. Bacteria present in dental plaque which forms on the surface of the teeth and in the periodontal pocket contribute to both the initiation and progress of periodontal disease. Thus, in order to prevent or treat periodontal disease, these bacteria must be suppressed by some means other than simple mechanical scrubbing. Towards this end, there has been a great deal of research aimed at developing therapeutic dentifrices, mouthwashes, and methods of treating periodontal disease, which are effective in suppressing these bacteria. However, periodontal disease involves more than the bacterial infection. Severe periodontal disease involves the destruction of periodontal tissue, which is primarily caused by the indirect effects mediated by the host's reaction to the bacteria in the periodontium and gingival sulcus, specifically inflammation.
As indicated, gingivitis is an inflammatory disease of the gingival and periodontium characterized by redness, swelling and bleeding upon probing. If left unchecked, gingivitis may progress into periodontitis, which may result in attachment loss, bone destruction and tooth loss. Anaerobic bacteria are generally regarded as the initiating agent of gingivitis, with subsequent progression and disease severity determined by the host immune response, i.e., inflammation, which is a nonspecific cellular and biochemical process involving multiple pro-inflammatory agents.
Bacterial metabolites induce leukocyte chemotaxis which results in the accumulation of inflammatory cells at the site of the bacterial challenge. Furthermore, bacterial metabolites induce the production of inflammatory mediators by leukocytic cells, in particular monocytes. Amongst these are local disease mediators such as metabolites of arachidonic acid, e.g. leukotrienes, prostaglandins and thromboxanes. Prostaglandins have been found to be particularly important in the metabolism and destruction of tissue and alveolar bone. Indeed, the production of prostaglandins in the periodontal tissues has been found to be an important mediator of the loss of alveolar bone in the periodontium. Patients with periodontal breakdown show an elevated prostaglandin E2 level both in the gingival tissue as well as in the crevicular fluid. Prostaglandins and thromboxanes are formed from arachidonic acid by an enzyme cascade, the first step of which is the cyclooxygenation by an enzyme called cyclooxygenase (COX). Inhibiting the cyclooxygenase would inhibit the formation of prostaglandins and thus reduce alveolar bone loss, and indeed certain cyclooxygenase inhibitors, particularly non steroidal anti-inflammatory drugs such as indomethacin and flurbiprofen have been found to markedly reduce the resorption of alveolar bone.
Once inflammation starts, the process can self-propagate even when the causative agent is removed. Therefore, an anti-bacterial, such as stannous, zinc, CPC and peroxide, in combination with an anti-inflammatory agent would be a more effective therapy for gingivitis than the conventional method of using anti-bacterial agents alone. The present invention involves such combination of particular anti-bacterial agents and anti-inflammatory agents in oral care compositions to effectively treat and prevent bacteria-mediated diseases of the oral cavity and thereby inhibit periodontal bacteria-induced systemic disease.